Behavioral neuroscience, also known as
biological psychology[1],
biopsychology, or
psychobiology[2]
is the application of the principles of biology, in particular neurobiology, to the
study of mental processes and behavior in human and non-human
animals. A psychobiologist, for instance, may compare the
unfamiliar imprinting behavior in goslings to the early attachment behavior in human
infants and construct theory around these two phenomena. Behavioral
Neuroscientists may often be interested in measuring some
biological variable, e.g. an anatomical, physiological, or genetic
variable, in an attempt to relate it quantitatively or
qualitatively to a psychological or behavioral variable, and thus
contribute to evidence based
practice.

History

The study of behavioral neuroscience dates back to Avicenna (980-1037), a Persian psychologist and physician who in The
Canon of Medicine, recognized physiological psychology in
the treatment of illnesses involving emotions, and developed a system for
associating changes in the pulse
rate with inner feelings, which is seen as an anticipation of the
word association test.[3]
Avicenna also gave psychological explanations for certain somatic
illnesses, and he always linked the physical and psychological
illnesses together. He explained that humidity inside the head can contribute to
mood disorders, and he recognized that this occurs when the amount
of breath
changes: happiness
increases the breath, which leads to increased moisture inside the
brain, but if this moisture goes beyond its limits, the brain would
lose control over its rationality and lead to mental
disorders.[4]

Behavioral neuroscience as a scientific discipline later emerged
from a variety of scientific and philosophical traditions in the
18th and 19th centuries. In philosophy, men like Rene Descartes proposed physical models to
explain animal and human behavior. Descartes, for example,
suggested that the pineal gland, a midline unpaired structure
in the brain of many organisms, was the point of contact between
mind and body. Descartes also elaborated on a theory in which the
pneumatics of bodily
fluids could explain reflexes and other motor behavior. This
theory was inspired by moving statues in a garden in Paris.[5]

Other philosophers also helped give birth to psychology. One of the
earliest textbooks in the new field, The
Principles of Psychology by William James (1890), argues that the
scientific study of psychology should be grounded in an
understanding of biology:

“

Bodily experiences,
therefore, and more particularly brain-experiences, must take a
place amongst those conditions of the mental life of which
Psychology need take account. The spiritualist and the
associationist must both be 'cerebralists,' to the extent at least
of admitting that certain peculiarities in the way of working of
their own favorite principles are explicable only by the fact that
the brain laws are a codeterminant of their result.

Our first conclusion, then, is that a certain amount of
brain-physiology must be presupposed or included in Psychology.[6]

”

James, like many early psychologists, had considerable training
in physiology. The emergence of both psychology and behavioral
neuroscience as legitimate sciences can be traced from the
emergence of physiology from anatomy, particularly neuroanatomy. Physiologists conducted
experiments on living organisms, a practice that was distrusted by
the dominant anatomists of the 18th and 19th centuries.[7]
The influential work of Claude Bernard, Charles Bell, and William Harvey
helped to convince the scientific community that reliable data
could be obtained from living subjects.

The term "psychobiology" has been used in a variety of contexts,
but was likely first used in its modern sense by Knight Dunlap in
his book An Outline of Psychobiology (1914).[8]
Dunlap also founded the journal Psychobiology. In the
announcement of that journal, Dunlap writes that the journal will
publish research "...bearing on the interconnection of mental and
physiological functions", which describes the field of behavioral
neuroscience even in its modern sense.[8]

Relationship
to other fields of psychology and biology

In many cases, humans may serve as experimental subjects in
behavioral neuroscience experiments; however, a great deal of the
experimental literature in behavioral neuroscience comes from the
study of non-human species, most frequently rats, mice, and
monkeys. As a result, a critical assumption in behavioral
neuroscience is that organisms share biological and behavioral
similarities, enough to permit extrapolations across species. This
allies behavioral neuroscience closely with comparative psychology, evolutionary psychology, evolutionary biology, and neurobiology. Behavioral neuroscience also
has paradigmatic and methodological similarities to neuropsychology, which relies heavily
on the study of the behavior of humans with nervous system
dysfunction (i.e., a non-experimentally based biological
manipulation).

Synonyms for behavioral neuroscience include biopsychology,
behavioral neuroscience, and psychobiology [9]. Physiological psychology is
another term often used synonymously with behavioral neuroscience,
though some authors would make physiological psychology a subfield
of behavioral neuroscience, with an appropriately more narrow
definition.

Research
methods

The distinguishing characteristic of a behavioral neuroscience
experiment is that either the independent
variable of the experiment is biological, or some dependent variable is biological. In other
words, the nervous
system of the organism under study is permanently or
temporarily altered, or some aspect of the nervous system is
measured (usually to be related to a behavioral variable).

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Disabling or
decreasing neural function

Lesions - A classic method in
which a brain-region of interest is destroyed or stimulated to
observe any resulting changes such as degradated or enhanced
performance on some behavioral measure. Lesions can be placed with
relatively high accuracy thanks to a variety of brain 'atlases'
which provide a map of brain regions in 3-dimensional stereotactic coordinates.

Chemical lesions - Neural tissue is destroyed
by the infusion of a neurotoxin.

Temporary lesions - Neural tissue is
temporarily disabled by cooling or by the use of anesthetics such as tetrodotoxin.

Transcranial magnetic
stimulation - A new technique usually used with human
subjects in which a magnetic coil applied to the scalp causes
unsystematic electrical activity in nearby cortical neurons which
can be experimentally analyzed as a functional lesion.

Psychopharmacological manipulations - A
chemical receptor antagonist induces neural
activity by interfering with neurotransmission. Antagonists can be
delivered systemically (such as by intravenous injection) or
locally (intracebrally) during a surgical procedure.

Enhancing neural
function

Electrical Stimulation - A classic method in
which neural activity is enhanced by application of a small
electrical current (too small to cause significant cell
death).

Psychopharmacological manipulations - A
chemical receptor agonist facilitates neural
activity by enhancing or replacing endogenous neurotransmitters. Agonists can be
delivered systemically (such as by intravenous injection) or
locally (intracerebrally) during a surgical procedure.

Transcranial magnetic stimulation - In some
cases (for example, studies of motor cortex), this technique can be
analyzed as having a stimulatory effect (rather than as a
functional lesion) .

Measuring neural
activity

Single-unit recording -
A method whereby an electrode introduced into the brain of a living
animal to detect electrical activity that is generated by the
neurons adjacent to the electrode tip. Normally this is performed
with sedated animals but sometimes it is performed on awake animals
engaged in a behavioral event. Such as a thirsty rat whisking a
particular sandpaper grade previously paired with water order to
measure the corresponding patterns of neuronal firing at the
decision point.[10]

Multielectrode recording - The use of a bundle
of fine electrodes to record the simultaneous activity of up to
hundreds of neurons.

fMRI - Functional magnetic
resonance imaging, a technique most frequently applied on human
subjects, in which changes in cerebral blood flow can be detected
in an MRI
apparatus and are taken to indicate relative activity of larger
scale brain regions (i.e., on the order of hundreds of thousands of
neurons).

Functional neuroanatomy - A more complex
counterpart of phrenology. The expression of some
anatomical marker is taken to reflect neural activity. For example,
the expression of immediate early
genes is thought to be caused by vigorous neural activity.
Likewise, the injection of 2-deoxyglucose prior
to some behavioral task can be followed by anatomical localization
of that chemical; it is taken up by neurons that are electrically
active.

Genetic
manipulations

QTL
mapping - The influence of a gene in some behavior can
be statistically inferred by studying inbred strains of
some species, most commonly mice. The recent sequencing of the genome of many species, most
notably mice, has facilitated this technique.

Selective breeding -
Organisms, often mice, may be bred selectively among inbred strains
to create a recombinant
congenic strain. This might be done to isolate an
experimentally interesting stretch of DNA derived from one strain on the background
genome of another strain to allow stronger inferences about the
role of that stretch of DNA.

Genetic engineering - The
genome may also be experimentally-manipulated; for example, knockout mice can be engineered to lack a
particular gene, or a gene may be expressed in a strain which does
not normally do so (the 'knock in'). Advanced techniques may also
permit the expression or suppression of a gene to occur by
injection of some regulating chemical.

Topic areas in
behavioral neuroscience

In general, behavioral neuroscientists study similar themes and
issues as academic psychologists, though limited by the need to use
nonhuman animals. As a result, the bulk of literature in behavioral
neuroscience deals with mental processes and behaviors that are
shared across different animal models such as:

Sensation and perception

Motivated behavior (hunger, thirst, sex)

Control of movement

Learning and memory

Sleep and biological rhythms

Emotion

However, with increasing technical sophistication and with the
development of more precise noninvasive methods that can be applied
to human subjects, behavioral neuroscientists are beginning to
contribute to other classical topic areas of psychology,
philosophy, and linguistics, such as:

Language

Reasoning and decision making

Consciousness

Behavioral neuroscience has also had a strong history of
contributing to the understanding of medical disorders, including
those that fall under the purview of clinical psychology and biological psychopathology
(also known as abnormal psychology). Although animal models for all mental illnesses do
not exist, the field has contributed important therapeutic data on
a variety of conditions, including:

Parkinson's Disease, a degenerative
disorder of the central nervous system that often impairs the
sufferer's motor skills and speech.

Huntington's Disease, a rare inherited
neurological disorder whose most obvious symptoms are abnormal body
movements and a lack of coordination. It also affects a number of
mental abilities and some aspects of personality.

Alzheimer's Disease, a neurodegenerative
disease that, in its most common form, is found in people over the
age of 65 and is characterized by progressive cognitive
deterioration, together with declining activities of daily living
and by neuropsychiatric symptoms or behavioral changes.

Clinical depression, a common psychiatric
disorder, characterized by a persistent lowering of mood, loss of
interest in usual activities and diminished ability to experience
pleasure.

Schizophrenia, a psychiatric diagnosis
that describes a mental illness characterized by impairments in the
perception or expression of reality, most commonly manifesting as
auditory hallucinations, paranoid or bizarre delusions or
disorganized speech and thinking in the context of significant
social or occupational dysfunction.

Autism, a brain
development disorder that impairs social interaction and
communication, and causes restricted and repetitive behavior, all
starting before a child is three years old.

Anxiety, a physiological
state characterized by cognitive, somatic, emotional, and
behavioral components. These components combine to create the
feelings that are typically recognized as fear, apprehension, or
worry.

Nobel
Laureates

The following Nobel
Prize winners could reasonably be considered biological
psychologists. (This list omits winners who were almost exclusively
neuroanatomists or
neurophysiologists; i.e., those that
did not measure behavioral or psychological variables.)